Friction draft gear



G. W. WlLDlN FRICTION DRAFT GEAR Filed May 15, 1930 5 Fi 32 4/ 40,5336/6 303/ /4 zo Feb. 9, 1932.

ATToRNEw Patented Feb. 9, 1932 GEORGE W. WILDIN, F PITTSBURGH,PENNSYLVANIA, ASSIGNOR TO CARDTFJ'ELL WEST- Ih'l'G-HOUSE COMPANY, ACORPORATION OF DELAWARE FR'CTION DRAFT GEAR Application filed. May 15,1930. Serial No. 452,761.

The object of the invention is to'provide an improved draft gearespecially adapted for installation in passenger coaches, in which minorshocks will be absorbed by spring buffer action and the `more severeshocks absorbed by friction shock-absorbing means.

Itis an obj ect to provide a unitary assembly of a friction draft gearand buffer springs which will occupy the standard. space provided in theusual yoke, and which can be handled and installed as an ordinary draftGear.

b Other objects of the invention are to provide adraft gear which iscomposed of inner and outer telescoping casings, the outer casingcontaining buer springs and the inner casing containing the frictionelements; to provide for a detachable assembly of the fric` tion casingand the buffer casing; and to provide a simple, reliable and ruggedconstruction which will function regularly under all conditions ofservice. Y Y v These and other objects of the invention will becomeapparent from the following description and the accompanying figuresattached.

In the accompanying drawings: Fig. 1 is a vertical longitudinal sectionof a draft gear embodying the invention;

Fig. 2 is a horizontal longitudinal section of the same gear asinstalled in a railway passenger or freight car, showing in addition theportions of the draft or center sills of the car, stop plates, yoke andcoupler butt; and

Fig. 3 is a vertical transverse section of the draft gear shown in Fig.2, on the line 3 3 marked thereon.

With reference to the drawings, the draft rigging comprises the centeror draft sills 6 cfa car underframe, to which ar-e'secured,

by proper means, the front stop lugs7, 7

and the rear stop lugs 8, 8. The inner end of the draw-bar 9 isconnected by conventional means (not shown)V to the yoke 10, which is ofthe usual standard form. A follower plate 11 is placed within the yokeVand supported thereby. The yoke itself is supported in the conventionalmanner by a detachable saddle (i0` plate 19., bolted to the draft sillsas shown.

The draft gear'mechanism itself comprises two telescoping casings, anouter casing 13 and an inner casing 14. The outer casing 13 issubstantially rectangular in form, and is provided with side walls15,15, top and-bottom walls 16, and the rear end Wall 17. The side walls15 iit snugly within the draft sills 6, as shown in Fig. The innercasing 14 comprises a hollow rectangular shell provided with side walls18, top and bottom walls 19, and the rear end wall 20. The side wallsmay be recessed for a. portion of their length, as indicated at 21, orthe structure may be otherwise lightened within the required. limits ofits strength. v

The length of the innercasing 14 ismuch less than that of the casing 13,so that upon assembly (as shown in Fig. 2) it is substantially enclosedthereby and space is provided between the end walls of the two for thespring unit of the gear. The outer casing 13 is shown as comprising asubstantially rectangular block of metal, provided with a very thickrear wall 17 the face of which is shown at 24. The wall 17 isvprovidedwith two parallel cylindrical pockets 22. rlhe side walls 15 of thecasing 13 `may be cut away, as indicated at 23, 23 (Figs. 2 and 3), toafford clearance for the springs.

The pockets 22 are located at each side of the longitudinal center lineof the outer casing 13. The inner face of the rear wall 17 comprises avertical face 24, coeXtensive in area with the rearface of the casing14. 'The face 24, therefore, provides a stop which i limits the inwardmovement of the casing 14. As indicated in Figs. 2 and 8, heavy coilsprings 25 and 26 are mounted in each of the i pockets provided. Theouter springs 25 are much heavier than the inner springs 26. Studs 45,facing inwardly from the bottom of the pockets 2Q, Vand studs 46,extending outwardly from the rear wall 2O of the inner casing 14, centerthe springs 26 with respect to the-pockets.

The springs 25 and 26 bear against the rear wall 17 of the outer casing`18, and on the opposite end bear against the rear wall 2O of the innercasing 14, and they thus normally maintain the inner'casing 14 extendedThe friction shock absorbing mechanism` is housed in the inner casing14, and is composed of the following elements: Adjacent the front end ofthe inner casing is disposed a group of alternate friction plates 27,28, placed upon the opposite sides of a wedging mechanism. The plates 28are anchored to the casing 14, and the plates 27 are movable `andnormally bearagainst the follower plate 36, which is held in position bythe resistance springs 29 and A30.

The wedging mechanism comprises longitudinally 'placed wedge blocks 32,33, having opposed wedging faces which engage corresponding fac-es uponwedge blocks 34, 35, located, respectively, on either side of the wedge'block 32. As will be seen from the drawings, Ythe wedge block 33 isalso normally .engaged by kthe follower plate 36.

A release spring 31 at one end pressed upon the Ainner rear face ofthecasing 14, and at its other end 'bears upon a spring follower 38, whichtransmitsthe pressure through the stem-37 of the wedge-block 32. rlhekey 39, driven through slots 40 provided in the outer -casing andthrough cooperating slots 41 provided in the inner casing, passesthrough an opening in the stem 37, and thus securely locks the bufferand friction gear in an assembled position.

To prevent the key 39 from being dislodged,'a depression 42 is formed inits rear faceinto 4which a projection or detent 43 eX- tends from thefollower' 38. The key 39 fits the apertures 41 closely, and hence has nomovement longitudinally of the 'casing 14, while the slots 40'areelongated at leastto the extent of the normal clearance provided betweenthe face 24 and the rear wall 20 of the casing 14.

The friction unit of the gear has av much greater capacity than that ofthe spring unit,

the ratio being in practice about three to one.

wall 2O make Contact. With the further relative approach of the follower11 and the casing 14, the resistance is primarily by the :springs housedwithin the casing 14, plus the friction which is developed between thewedge shoes 34, 35, and the plates 27 against which they bear.

Because of the slight taper of a pair of the anchored plates 28, both ofthe resisting agents are rapidly augmented. The inward lateral movementof the shoes, caused by this tapered form, urges the wedge 33 forward.As soon as the follower 11 comes into contact with the plates 27, thelatter are moved longitudinally relatively to the plates 23, therebydeveloping greatly increased friction, which continues to be augmentedby the action of the tapered plates until the gear is completely closedby the engagement of the follower 11 with the end of the casing 14.

Modifications and rearrangements may be made within the scope of theinvention, in

which the action is in full accord with the principles herein set forth.

I claim as my invention 1. In a draft gear, in combination, a housingcontaining friction shock absorbing means including intercalatedfriction plates, wedge means compressing the plates together andresistance springs opposing the movevment of said plates, a second openended housing surrounding the housing first named and in which the saidfriction housing is slidable longitudinally, buhng springs interposedbetween said rst and second housings, and a bar extending transverselythrough both housings and having lateral lost motion with respect to oneof them for limiting the movement of one housing with respect to theother. I A

2. In a draft gear, an open ended housing, a second housing closing theopening and slidable in said first-named housing, a buil'- ing spring inthe closed. space between the two housings, a projection on one of Vthehousings limiting the relative approach beyond the capacity of thespring, frictional shock absorbing means including intercalated platesand resistance springs therefor contained in said secondhousing, and abar extending transversely through both housings and having lateral lostmotion with respect'4 to one of them for limiting the outward Vmovementof the second housing with respect to the first and serving to maintainan initial compression upon all springs in both housings.

3. In a draft gear, in combination, a' casing having a closed endadapted to cooperate with a pair of stop lugs, the opposite end of thecasingbeing open, a second casing of like form freely slidable withinthe firstnamed casing having its open end similarly directed, expansionsprings reacting between the closed ends of the two casings, a columnlimiting the relative approach of the closed ends of the casings, astop-'engaging follower facing the open ends of the casings, ashockabsorbing unit housed within the secondnamed casing and comprisingfriction plates and wedges, one of the latter bearing upon the follower,spring means reacting between the plates andl Wedges and the closed endof the casing and a bar extending transverse- 1y through both casngs andhaving lateral 10st motion with respect to one 0f them for limiting therelative movement of the two casings, such bar also passing through thefollowenengaging wedge whereby the friction elements are held within thesecondnamed casing.

In testimony whereof I ax my signature.

GEORGE W. WILDIN.

